Data file
What is a .dat file?
A .dat file is a generic data file. It has no single owner — any program can dump data into a .dat, so what it is depends entirely on which program made it. Most of the time it's a file you're not supposed to open by hand.
Never run a .dat file. If double-clicking prompts you to run something, cancel.
This extension has been used by more than one format
6 different formats have claimed .dat over the years, so two files with the same extension aren't necessarily the same kind of thing.
How to open a .dat file
- WindowsThe program that created it (most common answer)
- WindowsNotepad, to peek at whether it's text
- WindowsVLC, if it came from a video download
- MacTextEdit for a quick look
- MacVLC for media .dat files
- Linux`file yourfile.dat` in the terminal tells you what it actually is
How to convert a .dat file
- If the .dat is really a video (common with VCD rips), rename it to .mpg or open it in VLC.
- winmail.dat comes from Outlook — use a winmail.dat viewer to pull out the real attachments.
- If it opens as readable text, save it as .txt or .csv from your text editor.
The technical record
For archivists, developers and the merely curious: these are the PRONOM registry entries for .dat.
| Format name | Version | MIME type | PUID |
|---|---|---|---|
| Mork | — | — | fmt/612 |
| CD-ROM/XA (eXtended Architecture) | — | — | fmt/819 |
| NMRPipe | — | — | fmt/1228 |
| ESRI ArcInfo DAT File (External) | — | — | fmt/1594 |
| Data File | Generic | — | fmt/1730 |
| Help Librarian File | — | — | fmt/1790 |